The invention relates to thermal imaging. More particularly, the invention relates to flash thermal imaging.
Flash thermal imaging inspection methods and apparatus are shown in U.S. Pat. Nos. 6,542,849 and 6,712,502 (the '849 and '502 patents respectively, the disclosures of which are incorporated by reference herein as if set forth at length). A basic thermal imaging system includes a light source (e.g., one or more flash lamps) and a detector (e.g., an infrared imaging camera). The source and detector are coupled to a control system to control inspection of a workpiece. After a flash from the source illuminates a surface of the workpiece, the detector is used to obtain a time series of readings or images of light radiated from the surfaces. The decay properties of such radiated light may be used to evaluate the workpiece. Such techniques may be used to evaluate material thickness, the presence of defects in the material, and the like.